My bad - the mathematician in me read it as written...
To answer your question as intended:
The TriAxis is probably capable of a wider array of sounds than a standalone amp and has the advantage of being able to consistantly reproduce those sound due to its MIDI programmable nature. The Mark V is capable of producing only three basic sounds at a time (without adjustment - 6 if you include the switchable EQ) - more than enough for gigging - and has the advantage of portabilty and price over the Triaxis / 2:90 combination (2k for a Mark V head new, 2100 for the Mark V combo new, 2200 for a clean, used Tri / 2:90 and a cheap rack). The Tri / 2:90 is stereo, the Mark V is not.
I think to better answer your question you need to determine the what and where of your playing situation. Do you gig? Various styles? What do you drive?
I own a Triaxis which I currently use with a 20/20 (I own a 2:90 but I need larger rack before I can use it regularly). I have it programmed for 2 sets of 4 sounds - clean, crunch, lead1 and lead2 - for single coil and humbucking guitars. My rack includes the standard effects, audio loops and pedals - I built a custom pedalboard for it. It sounds great! It cost me about $5500 and 1 year to assemble (including speakers). It spends most of it's time in the rehearsal studio and comes out about one a month for gigs. For pickup stuff, jams and tiny stages I use a combo amp (often just guitar-cord-amp).
I would love to have a Mark V or (IV) head to use with 1 (or more) of my Thiele cabs with a small rack for effects. Easy to carry and flexible in nature. And, with any luck, by this time next year that will be the case. But then, I already have the Tri / 2:90.
So if you can define your requirements for use, I think the answer becomes obvious.
On the other hand, if this is just GAS, you'll probably buy both eventually. :lol:
jbw